Montana Code Annotated Title 40, Chapter 4 - Dissolution of Marriage

Montana is a purely no-fault divorce state. The only ground for dissolution is that the marriage is 'irretrievably broken.' The filing spouse must have been domiciled in Montana or stationed in the state as a member of the armed services for at least 90 days before filing. The court must find either that the parties have lived separate and apart for more than 180 days or that there is serious marital discord adversely affecting one or both parties. If one spouse files for legal separation and the other requests dissolution, the court must grant a dissolution instead.

Effective: 2025

If both spouses state under oath that the marriage is irretrievably broken, or one spouse states it and the other does not deny it, the court must find the marriage irretrievably broken after a hearing. A finding of irretrievable breakdown means there is no reasonable prospect of reconciliation. If one spouse denies the breakdown, the court may continue the case for 30 to 60 days and suggest counseling, but cannot compel counseling.

Effective: 2025

A dissolution proceeding is commenced by filing a petition. Montana has abolished all traditional fault-based defenses to divorce, including condonation, connivance, collusion, recrimination, insanity, and lapse of time. Neither spouse can block a divorce by raising any of these defenses.

Effective: 2025

Montana is an equitable distribution state. The court must equitably apportion all property and assets belonging to either or both spouses, regardless of when acquired or whose name is on the title. The law creates a presumption of common ownership in all marital property. The court considers: duration of the marriage, age, health, occupation, income, vocational skills, employability, liabilities, needs of each party, custodial provisions, whether the division replaces maintenance, contributions to the marital estate including homemaking, and any dissipation of value. Marital misconduct cannot be considered in property division.

Effective: 2025

Spouses may enter a written separation agreement covering property division, maintenance, child support, and parenting. The court must approve it unless it finds the terms unconscionable after reviewing the parties' economic circumstances. Once incorporated into the decree, the agreement is enforceable as both a court judgment and a contract. The agreement can expressly limit future modification of property and maintenance terms.

Effective: 2025

Within 60 days of being served with a dissolution petition, each spouse must serve a preliminary declaration of disclosure on the other, listing all assets, liabilities, income, and expenses. Declarations are made under penalty of perjury. A court may set aside a judgment within 5 years if it discovers perjury in a final declaration. Parties may waive or modify disclosure timelines by written or oral stipulation in open court.

Effective: 2025

When a dissolution petition is filed, an automatic economic restraining order takes effect, preventing either spouse from dissipating, transferring, encumbering, or hiding marital assets. Either party may ask the court to expand, limit, modify, or revoke the order. Violations can result in sanctions and contempt of court. The restraining order dissolves when the case is dismissed or the final decree is entered.

Effective: 2025

The court determines all parenting arrangements based on the child's best interest. Factors include: each parent's wishes, the child's wishes, the child's relationships with parents and siblings, adjustment to home, school, and community, mental and physical health of all parties, physical abuse or threats, chemical dependency, continuity and stability of care, developmental needs, failure to pay birth-related costs or child support, and whether frequent contact with both parents serves the child's interest. A parent's military service alone cannot be the basis for a parenting decision.

Effective: 2025

Every dissolution or legal separation involving children requires a final parenting plan. The plan must include: designation of a custodial parent (for legal purposes only), residential schedule with holidays and vacations, decision-making allocation, dispute resolution methods (other than court), sanctions for noncompliance, and provisions for the child's financial needs. Each parent may make day-to-day and emergency decisions when the child is in their care. One parent's failure to follow the plan does not relieve the other parent of their obligations.

Effective: 2025

A court may amend a prior parenting plan if circumstances have changed since the plan was entered and the amendment serves the child's best interest. Before amending, the court may refer parties to mediation unless domestic violence, child abuse, or substance abuse is present. When a parent's relocation significantly affects the child's contact with the other parent, the court must also weigh the feasibility of preserving the nonrelocating parent's relationship with the child.

Effective: 2025

A parent who intends to relocate must provide written notice to the other parent. If the move significantly affects the child's contact with the other parent, the relocating parent must file a motion to amend the residential schedule, served at least 30 days before the move. The other parent has 21 days to file a response with an alternate proposed schedule. Failure to respond within 21 days constitutes acceptance of the proposed new schedule.

Effective: 2025

Unless a parent has been denied custody or visitation rights by court order, both parents have equal access to all records and information about their minor child. This includes medical, dental, and school records. Neither parent can unilaterally block the other parent's access to the child's records.

Effective: 2025

The court may award maintenance to either spouse, but only after finding the requesting spouse lacks sufficient property to meet reasonable needs AND is unable to support themselves through appropriate employment, or is the custodian of a child whose condition makes employment inappropriate. Factors for amount and duration include: financial resources, time needed for education or training, comparative earning capacity, standard of living during the marriage, obligations and assets, marriage duration, age and health, the paying spouse's ability to pay, and any other relevant factors. Marital misconduct cannot be considered. There is no formula — judges have broad discretion.

Effective: 2025

The court must order one or both parents to pay child support in an amount that is reasonable and necessary, without regard to marital misconduct. Factors include: the child's financial resources, each parent's financial resources, the standard of living the child would have enjoyed, the child's physical and emotional condition, educational and medical needs, age, day care costs, the parenting plan, and any other support obligations. The Montana Child Support Guidelines (ARM 37.62) establish a presumptive amount that applies in all cases unless found unjust by clear and convincing evidence.

Effective: 2025

Maintenance or support orders can only be modified for installments accruing after notice of the modification motion. If the original decree included maintenance or support, modification requires a showing of changed circumstances so substantial and continuing as to make the original terms unconscionable. Property division generally cannot be modified except by written consent or fraud. Maintenance terminates upon the death of either party or the remarriage of the recipient unless otherwise agreed. Child support terminates at emancipation or high school graduation, whichever is later, but no later than age 19 — except for disabled children who remain financially dependent.

Effective: 2025

The Department of Public Health and Human Services adopts uniform child support guidelines (codified in Administrative Rules of Montana, Title 37, Chapter 62) used to determine minimum child support amounts. The guidelines consider both parents' incomes, allowable deductions, and the number of children. The department must review the guidelines at least every 4 years to ensure they produce appropriate support amounts. The guidelines apply in all cases, including defaults and agreed settlements.

Effective: 2025

To file for divorce in Montana, one spouse must have been domiciled in the state or stationed there as a member of the armed services for at least 90 days before filing. The petition is filed in district court. If a spouse files for legal separation, the other spouse can request the court convert it to a dissolution proceeding.

Effective: 2025

A decree of dissolution or legal separation is final when entered, subject only to the right of appeal. There is no mandatory waiting period after filing before a decree can be entered in a standard dissolution. Six months after a legal separation decree, either party may ask the court to convert it to a dissolution. Upon request, the court must restore a party's maiden name, birth name, or former name.

Effective: 2025

Montana offers a simplified summary dissolution procedure for qualifying couples. Both spouses must agree the marriage is irretrievably broken and meet residency requirements. Originally limited to couples with no children and no pregnancy, the 2025 legislature (SB 372) expanded eligibility to include couples with children who have an agreed-upon parenting plan. Additional conditions include limited property and debt thresholds.

Effective: 2025

Either spouse may request temporary orders for maintenance, child support, parenting arrangements, or restraining orders during the pendency of the dissolution or legal separation proceedings. Temporary orders remain in effect until the final decree is entered or until further order of the court.

Effective: 2025

The court may order parties in any family law proceeding to participate in mediation at any time, and any party may request it. Mediators must be selected from a court-maintained list, though parties can agree on an unlisted mediator. In cases involving domestic violence, mediation must be conducted by a mediator trained in mediating domestic violence cases. Mediation is strongly encouraged before trial in both property and parenting disputes.

Effective: 2025

The court may require parents to attend an educational program on the effects of dissolution on children. The program covers the impact of family restructuring on children's development and ways to minimize harm. This is commonly required in contested parenting cases to help parents focus on the children's needs during the divorce process.

Effective: 2025

Victims of partner or family member assault, sexual assault, or stalking may petition for a protection order. Temporary orders can be issued ex parte if there is imminent danger. Full protection orders may be permanent based on the severity of abuse and the respondent's history of violence. Orders can include no-contact provisions, exclusive possession of the home, and temporary parenting arrangements. Protection orders are entered into the National Crime Information Center (NCIC) database within 24 hours and are enforceable across state lines under the Uniform Interstate Enforcement provisions.

Effective: 2025

Montana has adopted the Uniform Premarital Agreement Act. A prenuptial agreement must be in writing and signed by both parties, but requires no additional consideration. It becomes effective upon marriage. A prenup is unenforceable if the challenging party proves they did not sign voluntarily, or that the agreement was unconscionable and they were not provided a fair disclosure of the other party's finances. Prenuptial agreements cannot adversely affect a child's right to support. Statutes of limitation are tolled during the marriage.

Effective: 2025

Upon request by either party whose marriage is dissolved or declared invalid, the court must order restoration of the party's maiden name, birth name, or a former name. This is handled as part of the dissolution decree — no separate legal proceeding is required.

Effective: 2025

The court may appoint a guardian ad litem to represent the child's interests in parenting disputes. The guardian investigates the child's circumstances and makes recommendations to the court. This appointment is discretionary and typically occurs in highly contested cases or when concerns about abuse, neglect, or parental fitness arise.

Effective: 2025

Montana criminalizes parenting interference. A person commits the offense if they knowingly take, entice, or withhold a child from the other parent without legal right, with the purpose of substantially depriving the other parent of their parenting rights. This applies both before and after a court order is in place. The penalty is up to 10 years imprisonment and/or a $50,000 fine. A first-time offender who has not left the state may avoid charges by voluntarily returning the child before arraignment.

Effective: 2025

A child's vaccination status may not be used as evidence or grounds for a parenting decision. The court cannot base custody or parenting time determinations on whether a parent has or has not vaccinated a child. This provision ensures medical decisions about vaccination do not become weaponized in parenting disputes.

Effective: 2025